BF3 Bond Angles

An explanation of the bond angles for BF3 (Boron trifluoride).

The ideal bond angle for the Boron trifluoride is 120° since it has a Trigonal Planer molecular geometry. Experimentally we would expect the bond angle to be approximately 120°.

To determine the bond angles for a compound like BF3, we complete the following steps:

1) Draw the Lewis Structure for the compound (for BF3: BF3 Lewis Structure: How to Draw the ...).
2) Predict how the atoms and lone pairs will spread out when the repel each other.
3) Use a chart based on steric number (like the one in the video) or use the AXN notation to find the molecular shape. This will be determined by the number of atoms and lone pairs attached to the central atom.
If you are trying to find the electron geometry for BF3 we would expect it to be Trigonal planer.

Helpful Resources:

• How to Draw Lewis Structures: How to Draw Lewis Structures: Five Ea...
• Molecular Geometry and VSEPR Explained: Molecular Geometry: Rules, Examples, ...
• Molecular Geo App: https://phet.colorado.edu/sims/html/m...
Get more chemistry help at http://www.breslyn.org

Drawing/writing done in InkScape. Screen capture done with Camtasia Studio 4.0. Done on a Dell Dimension laptop computer with a Wacom digital tablet (Bamboo).